Process for sulfation of aliphatic alcohols



April 7, 1953 J, K. FINCKE 2,634,287

PROCESS FOR SULFATION 0F ALIPHATIC ALCOHOLS Filed April 1, 1948 JOHN \CFINCJLG INVENTOR.

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complished substantially Patented Apr. 7, 1 953 UNITED PROCESS FOR SULFATION F ALIPHATIC ALCOHOLS John K. Fincke, Dayton, Ohio, assignor to Monsanto Chemical Company, St. Louis, Mo., a, cor- V poration of Delaware Application April 1, 1948, Serial No. 18,447

compounds involving the use of sulfur dioxide as a solvent and S03 as the sulfating agent.

In prior processes it has been proposed to carry out the sulfation of alcohols in liquid sulfur dioxide by indirectly precooling streams of the sulfating agent and the alcohol to be sulfated, combining the streams in a zone at subatmospheric temperatures, then flowing the stream into a second zone at a temperature higher than the first zone and then dilutin the product with water in order to stop the reaction.

According to my invention, sulfation is acinstantaneously by mixing together a stream of liquid S02 contalning an aliphatic alcohol and stream of liquid S02 containing dissolved $03. In the preferred form of my invention streams are mixed together in a mixing zone comprising preferably a short, tubular nozzle, then sprayed out into a chamber maintained at substantially atmospheric pressure. I have found that when operating in this manner the pressure drop across the spray nozzle is at least 40 pounds per square inch and less than 100 pounds per square inch. This corresponds to from 200 to 500 times the pressure drop obtained when the correspondving mass of liquid flows through the same nozzle. As a result of the reaction heat generated by the evaporation of an equivasulfation reaction,

liquid S02 occurs in the nozlent amount of the zle, the formation of the gaseous $02 in this manner accounting for the observed large pres; sure drop therein. The resulting mixture or 'sulfated product and vaporized S02, leaving the nozzle at high velocity sprays into the collection chamber which is designed to separate the sulfated alcohol products from the vaporized gaseous S02. Both products, namely, the sulfated alcohol product and the vaporized sulfur dioxide may thereafter be recovered in any suitable manner.

The pressure drop across the nozzle when the takes place inthe nozzle is 6 Claims. (01. zoo -459) 2 times that observed for the same mass flow of liquid. The pressure drop depends upon the rate of evaporation of S02 which in turn de ends upon the heat of sulfation and rate of reaction of the alcohols treated and to a lesser extent upon the degree of dilution of the reactants. The temperature of sulfation, which may be controlled by the amount of S02 used as solvent for the reactants, should be at least 20 C. and not substantially in excess of 75 C. By usin smaller proportions of solvent S02, the temperature of sulfation will be higher than when using larger quantities and vice versa. Except as explained above, th proportion of S02 present during the reaction is not critical as far as h reaction itself is concerned. However, as stated, by varying the proportions of liquid S02 used as the solvent the temperatures may be varied within the range indicated.

By reason of the fine state of subdivision of the sulfation product leaving th nozzle, any liquid or gaseous S02 in the product is rapidly and completely separated and removed therefrom.

As contrasted with previous processes, the present process of sulfation takes plac under adiabatic conditions; in other words, there is no gain or loss of heat to the system. The reaction takes place at temperatures of at least 20 C., but below C., and is completed as f r "as it is possible to ascertain in the space of time cohols which may be sulfated by my process ar the following:

c yi Methyl Ethyl 2-ethylhexyl Propyl Decyl Butyl 'Lauryl Secondary isobutyl 'I'etradecyl' Hexyl Octadecyl or any mixtures thereof. Polyhydric alcohols such as ethylen glycol, polyethylene glycol or glycol or polyglycol esters of fattyacids or the corresponding ethers of aliphatic alcohols may also be employed; contemplated. are. the

monoand diglycerides of fatty acids or mixtures of such glycerides.

I have found that the S03 combines quantitatively with the -OH group of th alcohol molecule and that it is possible to introduce as many S03 groups as there are --OH groups present in the molecule. This is done merely by proportioning the S03 present in the liquid S02 stream entering the mixing nozzle so that it contains the number of molecules which it is desired to introduce into the alcohol compound. The product formed is the sulfuric acid ester: ROSOsH.

The process is carried out by preparing separate solutions of sulfur trioxide in liquid S02 and of the alcohol to be sulfated dissolved in liquid S02. These solutions are stored in pressure vessels under a pressure corresponding substantially to the vapor pressure of the respective solutions. From the pressure vessels thev solutions are withdrawn by means of suitable pipes which connect with a nozzle of relatively short length. The solutions when caused to fiow into the nozzle become intimately mixed therein, sulfation of the alcohol takes place and heat of reaction is thereupon liberated. The liberated heat causes vaporization of S02 within the nozzle. The large volume of gas liberated within the nozzle causes a pressure drop which is at least 200 times and may be as high as 500 times that of the corresponding mass flow of liquid material. The pressure drop across the nozzle during sulfation has been found to be at least 40 pounds per square inch and usually less than 100 pounds per square inch. When liquid S02 is passed through the same nozzle the pressure drop is about 0.2 pound per square inch.

The mixture of gaseous S02 and liquid sulfation product is collected in a gas-liquid separating chamber operating at substantially atmospheric pressure. The vaporized S02 being waterfree is economically recovered, compressed and liquefied without further purification for reuse in the process. The sulfated hydroxy compound is neutralized with caustic alkali to produce the alkali metal salts of the corresponding sulfuric acid esters.

Reference is made to the single figure of the drawing showing in diagrammatic form apparatus suitable for carrying out the present process. Referring to the drawing, numeral I indicates a tank suitable for containing a sulfur dioxide solution of sulfur trioxide. Tank 2 contains liquid sulfur dioxide. Tank 3 contains the alcohol to be sulfated. Tanks I, 2 and 3 are, supported upon scales 4, 5 and 6, so that the contents of the tank may from time to time be weighed. Tanks I and 2 are provided with pressure gauges I and 6, respectively, and also with connections 9 and It for introducing liquid S02 from pipe I I. Tanks I, 2 and 3 are provided with bottom outlets and valves l2, I3 and I4, respectively, for controlling the flow'of the contents thereof into pipes I5, I6 and II, respectively. The liquid sulfur dioxide containing dissolved S03 fiowing through pipe I5 passes through fiowmeter I3, then through pipe I9 and enters mixing nozzle 20. Likewise the flow of liquid S02 in pipe I6 passes through flowmeter 2| into pipe 22.

The alcohol in tank 3 flows by means of pipe I! into pump 39, whereby it is forced through pipe 23 into fiowmeterM into pipe 25.. The respective liquids flowing into pipes 22 and 25 are combined in pipe 26, wherein the alcohol dissolves in the liquid sulfur dioxide forming a solution thereof. Pipe-26 connects with nozzle 26.

alcohol is carried out Nozzle 20 is contained within chamber 21, which may be an empty tank of relatively large volume or preferably a tower provided with a packed section 28 consisting of Raschig rings or other suitable packing or filtering material. The ends of the tower are closed by means of flanges 29 and 30. An exit for liquid sulfation product is provided at 3| and a gas exit is provided at 32. Pipe 33 connects with an additional liquid gas separator 34 also provided with liquid outlet 35 and gas outlet 36. The sulfated product is withdrawn mainly by means of pipe 3I with usually a small amount being recoverable at the outlet of pipe 35. The vaporized S02 leaving gas separator 34 by means of pipe 36 may be compressed and liquefied by means not shown and returned as liquid sulfur dioxide to pipe II for reuse in the process.

For control purposes a manometer 31 is provided for indicating the pressure in collecting zone 27. A thermocouple 38 is also provided with its junction adjacent nozzle 26 for indicating the temperature of the nozzle and the contents therein.

The process may be illustrated by the following examples:

EXAMPLE 1 Decyl alcohol suZfate. The apparatus shown in the drawing was utilized, the nozzle 20 being a 0.037" I. D. tube, 0.5" long.

Sufiicient S02 is dissolved in liquid S02 in tank I to form a 30% by weight solution. Decyl alcohol is added to tank 3 and liquid S02 is added to tank 2. The flow of the S02-S02 solution from tank I is adjusted to the alcohol flow from tank 3 so that slightly more than one mole of S03 is supplied to nozzle 20 for each mole of decyl alcohol entering the nozzle. The amount of S02 from tank 2 is proportioned to the decyl alcohol flow so as to give an approximately 40% by weight solution in pipe 26. During the run, the temperature of the nozzle ranged from 25 C. to 48 C. Decyl alcohol sulfate in good yields is recovered from pipe 3|.

EXAMPLE 2 Tetradecyl alcohol suZfater-Sufiicient S02 is dissolved in liquid S02 in tank I to form a 25% solution. Tetradecyl alcohol is loaded into tank 3 and liquid S02 is placed in tank 2, which may be heated if desired. The flow of tetradecyl alcohol from tank I and S02 from tank 2 is adjusted so that the solution in pipe 26 contains approximately 50 by weight of tetradecyl alcohol. The flow of the S02-S03 solution in tank I is adjusted to supply one mole of $03 to nozzle 26 for each mole of tetradecyl alcohol supplied by pipe 26 to nozzle 20. Tetradecyl alcohol sulfate is obtained at outlet 3I.

EXAMPLE 3 Laur'yl alcohol sulfate-The sulfation of lauryl as described in Example 2 above, with the exception that the concentration of the alcohol-S02 solution in pipe 26 is adjusted to by weight of alcohol. Other suitable concentrations maybe employed.

EXAMPLE solved aliphatic hydroxy of the SOz-SO: solution entering nozzle 20 is adjusted so as to provide two moles of S03 per mole of ethylene glycol in nozzle 20. The nozzle temperature was 50 C. The disulfate of ethylene glycol is obtained at outlet 3|.

EXAMPLE 5 Ethz'omc acid-This compound is prepared by the methods described in the Example 2 above, with the exception that ethyl alcohol is employed in place of the tetradecyl alcohol. The proportion of S03 supplied by means of pipe I9 is so proportioned as to furnish two moles of S03 per mole of ethyl alcohol. The yield of ethionic acid is substantially quantitative.

EXAMPLE 6 Lauryl mono-glyceryl suZfate.--Glyceryl monolaurate is sulfated, utilizing the process described in the above examples. Employing one mole of S03 per mole of the glyceryl mono-laurate the mono-sulfuric ester of this alcohol is obtained. The sodium salt of the ester is made by neutralizing the sulfate with sodium hydroxide solution, the solution of the sodium salt dried upon a steam heated drum and the product obtained in a pure form. This material may be employed as a detergent.

In a similar manner other monoor diglycerides of fatty acids may be sulfated.

What I claim is:

1. In a process of solfation wherein a stream of liquid S02 containing dissolved S03 is mixed with a stream of liquid S02 containing a dissolved aliphatic hydroxy compound, whereby said hy droxy compound is suliated and heat of suliation is liberated, the step of flowing said mixed streams through a nozzle and completely evaporating said liquid S02 within said nozzle solely by means of said heat of sulfation, whereby said S03 becomes combined with said hydroxy compound at a temperature of at least 20 C.

2. In a process of sulfation in which a stream of liquid S02 containing dissolved S03 is mixed with a stream of liquid S02 containing a discompound, whereby said hydroxy compound is suliated and heat of sulfation is liberated, the step of flowing said mixed streams through a nozzle into a zone of lower pressure, complete evaporation of S02 occurring within said nozzle solely by means of said heat of sulfation, the pressure drop across said nozzle being at least 40 pounds per square inch.

3. In a process of sulfation in which a stream of liquid S02 containing dissolved S03 is mixed with a stream of liquid S0z-containing a dissolved aliphatic hydroxy compound, whereby said hydroxy compound is sulfated and heat of sulfation is liberated, the step of flowing said mixed streams into and through a nozzle at a temperature of at least 20 0., wherein evaporation of liquid S02 occurs solely by means of said heat of sulfation, and recovering a sulfation product of said alphatic hydroxy compound.

4. In a process of sulfation in which a stream of liquid S02 containing dissolved S03 is mixed with a stream of liquid S02 containing a dissolved aliphatic hydroxy compound, whereby said hydroxy compound is sulfated and heat of sulfation is evolved, the steps of mixing said streams and flowing the so-formed mixture through a. nozzle, wherein evaporation of liquid S02 occurs solely by means of said heat of sulfation and under substantially adiabatic conditions, said mixture thence flowing into a collection zone maintained at substantially atmospheric pressure.

. 5. In a process of sulfation in which a stream or" liquid S02 containing dissolved S03 is mixed with a stream of liquid S02 containing a dissolved aliphatic hydroxy compound, whereby said hydroxy compound is sulfated, and heat of sulfation evolved, the steps of flowing said streams together into a nozzle whereby evaporation of liquid S02 occurs solely by means of said heat of sulfation and without substantial gain or loss of heat by said flowing stream, and spraying said stream into a zone of reduced pressure.

6. In a process of sulfation in which a. stream of liquid S02 containing dissolved S03 is mixed with a stream of liquid S02 containing a dissolved aliphatic hydroxy compound, whereby said hydroxy compound is sulfated, and heat of sulfation evolved, the steps of flowing said streams together through a confined zone without substantial gain or loss of heat by said flowing stream,

and wherein complete evaporation of liquid S02 occurs solely by means of said heat of sulfation, and then spraying said stream into a zone maintained at substantially atmospheric pressure.

JOHN K. FINCKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,511,875 Edgar Oct. 14, 1924 1,913,794 Daimler et al June 13, 1933 2,235,098 Brandt et a1 Mar. 18, 1941 2,268,443 Crowder Dec. 30, 1941 2,290,167 Datin .i July 21, 1942 

1. IN A PROCESS OF SOLFATION WHEREIN A STEAM OF LIQUID SO2 CONTAINING DISSOLVED SO3 IS MIXED WITH A STREAM OF LIQUID SO2 CONTAINING A DISSOLVED ALIPHATIC HYDROXY COMPOUND, WHEREBY SAID HYDROXY COMPOUND IS SULFATED AND HEAT OF SULFATION IS LIBERATED, THE STEP OF FLOWING SAID MIXED STREAMS THROUGH A NOZZLE AND COMPLETELY EVAPORATING SAID LIQUID SO2 WITHIN SAID NOZZLE SOLELY BY MEANS OF SAID HEAT OF SULFATION, WHEREBY SAID SO3 BECOMES COMBINED WITH SAID HYDROXY COMPOUND AT A TEMPERATURE OF AT LEAST 20*C. 